Shri Ram had come up to the sea shore of Mumbai while he was searching Sita. At this place, he had installed a sand Shivlinga and originated a fresh water resource. The Balukeshwar temple is located on the same place and the fresh water is still flowing from the stream and is called Ban Ganga.
Valmiki Ramayana 1/69/1 to 9 Manas 3/32/2.
